Any corporation, firm, or partnership which may be registered hereunder as a mechanical contractor in the name of such corporation, firm or partnership shall have a master mechanical fitter who has submitted to the examination given by the examining board for mechanical fitters and installers and has thereby shown himself or herself fit, competent and qualified to engage in the business, trade, or calling of mechanical work, HVAC installation and gas piping as a bona fide officer of such corporation or as a member of such firm or partnership and who shall at all times be in actual charge of and be responsible for the mechanical work, HVAC installation, removal or repair of any gas fitting work done by such corporation, firm, or partnership. Before such corporation, firm or partnership shall be registered in its corporate, firm, or partnership name as a mechanical contractor, there shall be filed with the chief building official a certificate from the examining board of mechanical fitters showing the fitness and competency of such officer of such corporation or such member of such firm or partnership to engage in the business or calling of mechanical contractor; provided, if, after a certificate of registration is issued such corporation, such member of such firm or partnership shall withdraw there from and cease to be connected therewith, then and in that event the city council shall forthwith revoke the certificate of registration of such corporation, firm or partnership upon the request of the chief building official.